Through a 10-year collaboration between Boston University (BU) and the Massachusetts General Hospital (MGH), we have built insulin-only and bihormonal configurations of our bionic pancreas (BP) and extensively tested them in inpatient, outpatient, and real-world home-use studies in people with type 1 diabetes (T1D). We have also conducted preliminary clinical studies testing the insulin-only configuration of our BP in people with type 2 diabetes (T2D) and the glucagon-only configuration of our BP in people with chronic hypoglycemia. Over the past 3 years, we have built and tested progressive generations of a stand-alone, fully integrated, BP device, which we call the iLet, that integrates our micro-precision dual-infusion pump with a continuous glucose monitor (choice of either the Dexcom or Senseonics) and our clinically tested suite of mathematical control algorithms that autonomously determine and command insulin and glucagon doses based on continuous sensor glucose data. The development effort of the iLet platform began in the Co-PI's lab at BU in 2014 and was then translated to Beta Bionics in January 2016. Development of the third-generation iLet (the Gen 3 iLet) took place at Beta Bionics throughout 2017 and into early 2018. Our clinical partners at MGH and Stanford University will begin clinical trials testing the Gen 3 iLet in a home-use setting in adults with T1D in May 2018. The objective of this Fast Track application is to integrate all of the cumulative experience, technology, and innovation that we have assembled in the Gen 3 iLet, into the design and development of a highly reliable, easily serviceable, and commercially scalable, Gen 4 iLet, which is intended for broad distribution in the US and other worldwide markets. The objective of Phase I of this project is to leverage what we learn from the preclinical and clinical studies of the Gen 3 iLet to inform, define, and implement the final design and use requirements of our commercially scalable Gen 4 iLet and iLet disposables and to build the first clinical-ready devices suitable for the final pivotal trial required for a premarket approval (PMA) application to the FDA. The objective of Phase II is to progressively improve automation and scalability in the manufacturing and distribution processes that will make the Gen 4 iLet commercially viable and widely accessible to meet the largest possible demand it will need to serve. These objectives will be achieved with the following specific aims: (1) to implement the final design and use requirements of our commercially scalable Gen 4 iLet (and its associated disposables), which will be informed by data obtained from clinical studies of our Gen 3 iLet system, and then to build the first clinical-ready prototypes of the Gen 4 iLet system and submit the investigational device exemption (IDE) application to the US FDA for the Gen 4 iLet system, and (2) to acquire, install, and validate manufacturing machinery that will transition several of our manual assembly processes to fully or partially automated processes, thus optimizing the efficiency of our manufacturing operations by continuously improving and advancing the process and technology used in the production of the Gen 4 iLet and iLet administration set.